Grinding apparatus

ABSTRACT

Grinding apparatus for internal surfaces of clevises comprising a support frame having a table secured thereto for movement in a first horizontal direction, said table carrying a saddle mounted for horizontal movement in a second horizontal direction perpendicular to the first horizontal direction of movement. The saddle has a carriage mounted thereon adapted for vertical movement, said carriage having a rotatable spindle secured thereto upon which a grinding wheel is mounted. A work piece support table is pivotally mounted relative to the support frame such that the grinding wheel can be moved in directions parallel to three mutually perpendicular axes to grind surfaces on a stationary work piece.

Umted States Patent [191 [111 3,837,122 Ferguson Sept. 24, 1974 GRINDING APPARATUS Primary ExaminerOthell M. Simpson [76] Inventor: Charles N. Ferguson, 1623 X St., g Agent FlrmHoward Moore; Gerald Dallas, Tex. 75229 [22] Filed: Jan. 10, 1973 [57] ABSTRACT [21] App]. No.: 322,426

, Grinding apparatus for internal surfaces of clevises comprising a support frame having a table secured [52] U.S. Cl. 51/56, 51/109 thereto for movement in a first horizontal direction [51] Int. Cl B24b 7/00, B24b 9/00 said table carrying a Saddle mounted for horizontal [58] Fleld of Search 51/34 34 34 movement in a second horizontal direction perpendic- 5 1/56 57 ular to the first horizontal direction of movement. The saddle has a carriage mounted thereon adapted for [56] References Cited vertical movement, said carriage having a rotatable UN STATES PATENTS spindle secured thereto upon which a grinding wheel 2,518,018 8/1950 Jung 51/34 C is mounted. A work piece support table is pivotally 2,652,664 5 l a e al- 51/34 R mounted relative to the support frame such that the 3,146,551 9/1964 Carlsen et al..... 51/34 C grinding wheel can be moved in directions parallel to 3,750,342 Soderstrom 5 1/34 R three mutually perpendicular axes to grind surfaces on a stationary work piece.

10 Claims, 7 Drawing Figures GRINDING APPARATUS BACKGROUND OF INVENTION Surface grinders have been employed heretofore for grinding flat or plane surfaces. Two general types of grinding machines have been developed for this purpose, those of the planer type with a reciprocating table and those having a rotating work table.

Spindles upon which grinding wheels are mounted have been disposed both horizontally and vertically and have been employed in conjunction with reciprocating and rotating tables upon which the work piece is mounted.

In surface grinding the work piece is generally secured by a suitable fixture or clamping apparatus to the work table which moves the surface to be ground across the grinding face of the rotating grinding wheel.

Tool and cutter grinders of the universal type have been employed heretofore for sharpening cutting tools. Such machines are generally equipped with a head carrying the grinding wheel adapted for rotation about a vertical axis while the work piece is secured between a head stock and tail stock secured to a saddle for horizontal movement relative to the grinding wheel.

Commercial aircraft landing gear parts comprise struts and braces having perforated clevises and lugs for forming hinge joints therebetween. Aircraft landing gear parts are very expensive and are specially designed to carry high impact loads at minimum weights.

To repair landing gear parts damaged as a result of corrosion and wear, I have developed a process wherein tungsten carbide is sprayed onto bearing surfaces to provide a very hard corrosion resistant surface. However, grinding apparatus heretofore devised was not suited for grinding the hard tungsten carbide surface to accurate dimensions and for providing a smooth surface without overheating the base metal.

A further problem encountered in repairing damaged aircraft landing gear parts involved aligning the part in a grinding device since reference surfaces employed in manufacturing the parts were generally of no value since the surfaces were damaged by corrosion and wear.

SUMMARY OF INVENTION I have devised a grinding apparatus comprising a table having a saddle mounted thereon carrying a carriage. The table, the saddle and the carriage are movable in mutually perpendicular directions such that a grinding wheel on a spindle rotatably secured to the carriage can be moved relative to a stationary work piece for accurately grinding surfaces thereof.

The work piece is secured to a work support table which is pivotally mounted relative to the frame of the grinding apparatus to facilitate positioning an axis through perforations in a clevis perpendicular to a grinding face on the grinding wheel.

A strut of an aircraft landing gear is secured to the table and the table is moved to a position wherein the grinding face on the grinding wheel is perpendicular to the axis through the perforations in the clevis. The grinding face is then moved horizontally and vertically pendicular to the axis of the perforations or pin holes.

A primary object of the invention is to provide surface grinding apparatus particularly adapted for precision grinding of internal surfaces of clevises on aircraft landing gear parts.

Another object of the invention is to provide surface grinding apparatus having a grinding wheel movable in directions parallel to three mutually perpendicular axes relative to a stationary work piece which is of rigid construction and capable of grinding tungsten carbide surfaces.

A further object of the invention is to provide surface grinding apparatus particularly adapted for positioning the axis of a pin hole in a work piece perpendicular to the grinding face of a grinding wheel without reference to surfaces on the work piece other than the inner wall of the pin hole.

A still further object of the invention is to provide an improved method of securing a work piece having a perforated clevis thereon for grinding surfaces thereof.

Other and further objects of the invention will become apparent upon referring to the detailed description hereinafter following and to the drawings annexed hereto.

DESCRIPTION OF DRAWINGS Drawings of a preferred embodiment of the invention are annexed hereto so that the invention may be better and more fully understood, in which:

FIG. I is a side elevational view of the surface grinding apparatus;

FIG. II is a front elevational view;

FIG. III is a plan view of the grinder;

FIG. IV is an elevational view of the right side of the machine as viewed in FIG. II;

FIG. V is a fragmentary elevational view illustrating the method of positioning the axis through the perforated clevis perpendicular to the plane of the grinding wheel;

FIG. VI is a cross-sectional view taken along line VIVI of FIG. V; and

FIG. VII is a fragmentary perspective view of an auxiliary spindle mounting.

Numeral references are employed to designate like parts throughout the various figures of the drawing.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring to FIGS. I and II of the drawing numeral 1 generally designates a surface grinder having a base or support frame 2. A table 4 is movably secured to the upper surface of base 2 and moves from the front 2a of the base to the back 2b thereof. A saddle 6 is movably secured to table 4 and as viewed in FIG. II moves laterally across the upper surface of table 4.

Saddle 6 has a support post 8 extending upwardly therefrom along which a carriage 10 is movable as will be hereinafter more fully explained for moving grinding wheel 12 in directions parallel to three mutually perpendicular axes lying in horizontal and vertical planes.

The upper surface of base 2 has a bed 14 formed thereon which has suitable guide ways into which rails 15 on the lower surface of table 4 extend. Suitable means is provided for moving table 4 relative to base 2. In the particular embodiment of the invention illustrated in the drawing hand wheels 16 and 18 are secured to opposite ends of a screw 20 having a pinion gear (not shown) disposed in meshing relation with a rack gear secured to the bed 14 of the base 2 of the grinding apparatus.

It should be readily apparent that rotation of hand wheel 16 or 18 will impart rotation to screw 20 causing table 4 to be moved in a horizontal direction relative to base 2.

As best illustrated in FIG. III, table 4 comprises a substantially U-shaped member having rearwardly extending legs 4a and 4b extending outwardly from opposite sides of a central portion 4c which has bed 22 formed on the upper surface thereof.

Bed 22 comprises spaced parallel rails 23 which extend into guide slots formed in the lower surface of saddle 6. The central portion 4c of table 4 has suitable means mounted therein for imparting movement to saddle 6 in a horizontal direction transversely across table 4. In the particular embodiment of the invention illustrated in the drawing hand wheels 24, 26 and 28 are secured to shafts having pinion gears on ends thereof disposed in meshing relation with a rack gear 30 on the lower surface of saddle 6.

It should be readily apparent that rotation of any one of the hand wheels 24, 26 or 28 will impart longitudinal movement to saddle 6 for moving the saddle transversely across table 4.

Saddle 6 has a mounting plate 31 secured to a central portion thereof to which the lower end of support post 8 is secured. Carriage 10 is arranged to be moved vertically along post 8.

As illustrated in FIG. lV, carriage 10 comprises upper and lower plates 32 and 34 secured to upper and lower edges of a vertically disposed plate 36 forming a substantially channel shaped member.

Upper and lower plates 32 and 34 have aligned openings extending therethrough and a bearing 38 is secured therebetween for movement along post 8. Suitable means is provided to prevent rotation of carriage 10 about post 8. In the particular embodiment of the invention illustrated in the drawing, such means comprises a key 40 secured to post 8 and movable through a slot formed in bearing 38.

Suitable means is provided for moving carriage l vertically along post 8.

As best illustrated in FIG. IV a hand wheel 42 is secured to a shaft 44 having a bevel gear 45 on the end thereof disposed in meshing relation with bevel gear 46 secured to the upper end of screw 48. Screw 48 has a lower end rotatably secured to plate 30 on saddle 6 and extends through threaded apertures extending through upper and lower plates 32 and 34 on carriage 10.

It should be readily apparent that rotation of hand wheel 42 imparts rotation of screw 48 causing carriage to move vertically along post 8.

A spindle 50 extends through bearings 52 and 54 and through apertures formed in upper and lower plates 32 and 34 as illustrated in FIGS. II and IV of the drawing. The lower end of spindle 50 has a pulley 56 secured thereto and grinding wheel 12 is secured to the upper end thereof.

A motor 58 is secured to an end plate 60 secured between upper and lower plates 32 and 34 and connected to front plate 36. Motor 58 has a pulley 62 secured to the drive shaft thereof and a belt 64 ispositioned about pulley 62 andpulley 56 for imparting rotation to grinding wheel 12.

From the foregoing it should be readily apparent that rotation of hand wheel 42 moves grinding wheel 12 in a vertical direction and that rotation of hand wheel I6 moves grinding wheel 12 in a first horizontal direction while rotation of hand wheel 24 moves grinding wheel 12 in a second horizontal direction perpendicular to the first horizontal direction.

A work support table has opposite ends secured by trunnions 72 and 74 to elevating means adapted for adjusting the surface of table 70 relative to the grinding face of grinding wheel 12.

A first jack 76 is mounted in the base 2 of the grinding apparatus and is adapted to move in a vertical direction by rotation of hand wheel 78.

Trunnion 74 is secured to a slide element 80 arranged to move longitudinally along track assembly 82 secured to the upper end of jack 84. Jack 84 may assume any suitable configuration and comprises a housing 86 having a hand wheel 88 thereon for actuating same.

Work piece W may be secured to table 70 by any suitable means.

In. the particular embodiment of the invention illustrated in FIG. IV work piece W is supported by V- blocks 90 and 91 joined by a strap 92. Strap 92 is supported by spacer members 93 and 94 and is locked in position by C-clamps 95 and 96. Work piece W is secured relative to the V-blocks 90 and 91 by hold down straps 98 and 99 secured in position by anchor bolts 100.

From the foregoing it should be readily apparent that opposite ends of table 70 can be elevated independently by rotating hand wheels 78 and 88. Thus, the elevation of table 70 and the angle between the surface of table 70 and a horizontal plane are precisely controllable.

A preferred method of aligning surfaces S1 and S2 with an axis A of openings B passing through the clevis on work piece W is illustrated in FIG. V.

As has been hereinbefore pointed out surfaces S1 and S2 are not necessarily parallel to any other surfaces on the work piece W and are often angularly disposed relative to the longitudinal axis of work piece W. In repairing aircraft landing gear parts surfaces S1 and S2 are often worn and corroded such that these surfaces cannot be employed for aligning surfaces S1 and S2 with the grinding face of grinding wheel 12.

The axis A of openings B on work piece W is perpendicular to the plane in which surfaces S1 and S2 will lie after grinding has been accomplished.

A T-shaped gauge bar having a leg 102 and a cross member 104 is inserted through openings B in the clevis of work piece W and secured in a fixed position by a hold down strap 106 and bolt 108.

The upper surface of cross member 104 lies in a plane perpendicularto the axis A of openings B.

As a first step in aligning the upper surface of cross member 104 with the plane of the grinding face of grinding wheel 12 cross member 104 is preferably positioned to extend transversely of table 70.

Before bolts are tightened work piece W is rotated relative to table 70 about the longitudinal axis of the work piece W for aligning the upper surface of cross member 104 with the plane of the grinding face of grinding wheel 12. Such is accomplished by positioning a bar 105 having upper and lower surfaces which are parallel upon the upper face of grinding wheel 12.

A conventional dial indicator, for example, of the type commercially available from Brown and Sharpe Manufacturing Company is moved along the upper surface of bar 105 while the plunger 107 of the indicator moves across the upper surface of cross member 104.

Dial indicator 106 preferably has a dial graduated in thousandths of an inch and having a spindle travel equal to 2% revolutions of the hand. Thus, it should be readily apparent that if the hand on the dial indicator does not move as the indicator is moved along the upper surface of cross member 104 the line of travel is parallel to the line of travel along the upper surface of bar 105.

When the upper surface of cross member 104 is properly aligned, bolts 100 are tightened securing work piece W relative to table 70.

Bolt 108 is then loosened permitting rotation of cross member 104 preferably to a position substantially in alignment with the longitudinal axis of table 70.

Hand wheels 78 and 88 are then rotated to the desired position wherein the upper surface of cross member 104 after being repositioned is in alignment with the upper surface of bar 105 on grinding wheel 12.

It should be readily apparent that when two intersecting lines lying in a plane perpendicular to the axis A passing through openings B in the clevis are parallel to two corresponding lines lying in the plane of the grinding face of grinding wheel 12 that grinding wheel 12 can be moved across surfaces S1 and S2 in the clevis and the resultant surfaces will lie in parallel planes perpendicular to the axis A.

After work piece W has been properly oriented relative to grinding wheel 12 hand wheel 42 is rotated for positioning the grinding face of grinding wheel 12 at a proper elevation, for example, as illustrated in FIG. 1, relative to work piece W.

Hand wheel 16 is rotated for moving the edge of grinding wheel 12 into the clevis a desired distance and hand wheel 24 is rotated for moving the grinding face ofgrinding wheel 12 across surfaces S1 and S2 on work piece W.

The grinding wheel 12 is of the double cup type having diamonds in the rim which forms parallel upper and lower grinding faces. The wheel diameter is preferably 12 inches, the wheel thickness between grinding surfaces is one inch and the rim width is inch.

A modified form of the grinding apparatus is illustrated in FIG. Vll. Structure ofthe second embodiment which corresponds to structure of the first embodiment, illustrated in FIGS. l-Vl of the drawing, is designated by like reference characters. Only a description of structure different from that illustrated in the first embodiment is deemed necessary.

Table 4, saddle 6, and carriage are substantially identical to the corresponding structure illustrated in the first embodiment except that carriage 10 has a plate 60' secured to an end thereof by bolts 61' upon which motor 58' and auxiliary spindle 50' is mounted such that grinding faces of grinding wheel 12' lie in a vertical plane.

Work support table 70' (FIG. IV) is substantially vertically disposed having an upper end pivotally connected by a trunnion 72' to a side of base frame 2 of the grinding apparatus.

The lower end of work support table is pivotally connected by a trunnion 74' to a screw 84' which extends into an internally threaded collar 84" rotatably secured inside base member 1 and rotatable by a hand wheel 88.

From the foregoing it should be readily apparent that the angle of work support table 70' relative to a vertical plane is controllable by rotating hand wheel 88' thereby moving the lower end of work support table in a horizontal direction relative to the upper end thereof.

Support table 70' is moved into alignment with suitable support surfaces on work piece W and locked into position by tightening bolts securing work piece W relative to the table 70.

Hand wheels 16, 24 and 42 are rotated in the manner hereinbefore described for feeding grinding wheel 12' across surfaces S1 and S2 in clevises of the work piece W.

From the foregoing it should be readily apparent that the surface grinder accomplishes the objects of the invention hereinbefore discussed permitting the use of surfaces in perforated clevises for alignment relative to a grinding wheel expeditiously for accurately grinding surfaces inside clevis areas which could not be ground on surface grinders heretofore devised.

It should be appreciated that a description herein has been limited to preferred embodiments of my invention and that other and further embodiments may be devised without departing from the basic concept thereof.

Having described my invention, what I claim is:

1. Grinder apparatus comprising: a general frame; work support means; shaft support means movably secured to the frame; a shaft rotatably secured to the shaft support means; means to move the shaft support means and work support means relative to each other in horizontal and vertical directions; means to rotate the shaft; means to pivotally secure a first end of the work support means relative to the general frame; elevating means to pivot the work support means about an axis lying in a plane perpendicular to a plane in which the axis of the shaft is disposed; and means to pivotally secure said elevating means adjacent a second end of the work support means.

2. The combination called for in claim 1 wherein the shaft support means comprises a table movable in a first horizontal direction relative to the general frame; a saddle secured to said table movable in a second horizontal direction perpendicular to said first direction of movement; and a carriage secured to said saddle movable in a vertical direction relative to said saddle.

3. The combination called for in claim 1 with the addition of elevating means secured between the general frame and the means to pivotally secure a first end of the work support means relative to the frame.

4. The combination called for in claim 1 wherein the means to pivotally secure the elevating means comprises slide means pivotally secured to said work support means; and a track assembly secured to said elevating means, said slide means being supported on said track means.

5. A surface grinder comprising, a base; a table supported by said base; means to move said table in a first horizontal direction relative to said base; a saddle supported by said table; means to move said saddle relative to said tablev in a second horizontal direction perpendicular to said first horizontal direction; a carriage supported by said saddle; means to movably secure said carriage to the saddle for movement vertically relative to the saddle; a spindle on said carriage; means on said carriage for rotating said spindle; a grinding wheel on said spindle; a work support table; pivot means to secure a first end of said work support table to said base member; and adjustable means secured between said support table and said base means for pivoting said table about said pivot means.

6. A surface grinder comprising, a general frame; a spindle; a grinding wheel on said spindle; means to rotate said spindle; means to secure said spindle relative to said frame for movement in directions parallel to three mutually perpendicular axes; a work support table; pivot means securing an end of said work support table relative to the general frame; and adjustable means between said general frame and said support table for pivoting said table about said pivot means to establish and maintain a desired angular relationship between said work support table and said grinding wheel.

7. The combination called for in claim wherein said adjustable means comprises: a jack secured to said base; and a trunnion secured between said work support table and said jack.

8. The combination called for in claim 5 with the addition of: elevating means; a track assembly secured to said elevating means; slide means pivotally secured to said work support table, said slide means being supported by said track means.

9. The combination called for in claim 3 wherein said elevating means secured between the general frame and the means to pivotally secure the first end of the work means relative to the frame is adapted to permit movement of said work support means about a vertical axis.

10. The combination called for in claim 6 wherein said work support table is vertically disposed, said pivot means being secured adjacent an upper end of said work support table; and wherein said adjustable means is positioned to move a lower end of said work support table in a horizontal direction relative to the upper end of the work support table. 

1. Grinder apparatus comprising: a general frame; work support means; shaft support means movably secured to the frame; a shaft rotatably secured to the shaft support means; means to move the shaft support means and work support means relative to each other in horizontal and vertical directions; means to rotate the shaft; means to pivotally secure a first end of the work support means relative to the general frame; elevating means to pivot the work support means about an axis lying in a plane perpendicular to a plane in which the axis of the shaft is disposed; and means to pivotally secure said elevating means adjacent a second end of the work support means.
 2. The combination called for in claim 1 wherein the shaft support means comprises a table movable in a first horizontal direction relative to the general frame; a saddle secured to said table movable in a second horizontal direction perpendicular to said first direction of movement; and a carriage secured to said saddle movable in a vertical direction relative to said saddle.
 3. The combination called for in claim 1 with the addition of elevating means secured between the general frame and the means to pivotally secure a first end of the Work support means relative to the frame.
 4. The combination called for in claim 1 wherein the means to pivotally secure the elevating means comprises slide means pivotally secured to said work support means; and a track assembly secured to said elevating means, said slide means being supported on said track means.
 5. A surface grinder comprising, a base; a table supported by said base; means to move said table in a first horizontal direction relative to said base; a saddle supported by said table; means to move said saddle relative to said table in a second horizontal direction perpendicular to said first horizontal direction; a carriage supported by said saddle; means to movably secure said carriage to the saddle for movement vertically relative to the saddle; a spindle on said carriage; means on said carriage for rotating said spindle; a grinding wheel on said spindle; a work support table; pivot means to secure a first end of said work support table to said base member; and adjustable means secured between said support table and said base means for pivoting said table about said pivot means.
 6. A surface grinder comprising, a general frame; a spindle; a grinding wheel on said spindle; means to rotate said spindle; means to secure said spindle relative to said frame for movement in directions parallel to three mutually perpendicular axes; a work support table; pivot means securing an end of said work support table relative to the general frame; and adjustable means between said general frame and said support table for pivoting said table about said pivot means to establish and maintain a desired angular relationship between said work support table and said grinding wheel.
 7. The combination called for in claim 5 wherein said adjustable means comprises: a jack secured to said base; and a trunnion secured between said work support table and said jack.
 8. The combination called for in claim 5 with the addition of: elevating means; a track assembly secured to said elevating means; slide means pivotally secured to said work support table, said slide means being supported by said track means.
 9. The combination called for in claim 3 wherein said elevating means secured between the general frame and the means to pivotally secure the first end of the work means relative to the frame is adapted to permit movement of said work support means about a vertical axis.
 10. The combination called for in claim 6 wherein said work support table is vertically disposed, said pivot means being secured adjacent an upper end of said work support table; and wherein said adjustable means is positioned to move a lower end of said work support table in a horizontal direction relative to the upper end of the work support table. 